The present invention generally relates to the field of materials characterization. In particular, the invention relates to high throughput screens for evaluating the rheological properties of a material.
Currently, there is substantial research activity directed toward the discovery and optimization of polymeric materials for a wide range of applications. Although the chemistry of many polymers and polymerization reactions has been extensively studied, it is, nonetheless, rarely possible to predict a priori the physical or chemical properties a particular polymeric material will possess or the precise composition and architecture that will result from any particular synthesis scheme. Thus, characterization techniques to determine such properties are an essential part of the discovery process.
Combinatorial chemistry refers generally to methods for synthesizing a collection of chemically diverse materials and to methods for rapidly testing or screening this collection of materials for desirable performance characteristics and properties. Combinatorial chemistry approaches have greatly improved the efficiency of discovery of useful materials. For example, material scientists have developed and applied combinatorial chemistry approaches to discover a variety of novel materials, including for example, high temperature superconductors, magnetoresistors, phosphors and catalysts. See, for example, U.S. Pat. No. 5,776,359 to Schultz et al. In comparison to traditional materials science research, combinatorial materials research can effectively evaluate much larger numbers of diverse compounds in a much shorter period of time. Although such high-throughput synthesis and screening methodologies are conceptually promising, substantial technical challenges exist for application thereof to specific research and commercial goals.
With the development of combinatorial techniques that allow for the parallel synthesis of arrays comprising a vast number of diverse industrially relevant materials, there is a need for methods and devices and systems to rapidly characterize the physical and mechanical properties of the samples that are synthesized, such as the viscosity or related rheological properties of a material. There is also a particular need to reduce time involved in analyzing samples when transfer of the sample between locations is necessary. It would be especially attractive to rapidly test a plurality of samples on a common substrate, without needing to remove the samples from the substrate.
The characterization of materials using combinatorial methods has only recently become known. Examples of such technology are disclosed, for example, in commonly owned U.S. Pat. Nos. 6,182,499 (McFarland et al); 6,175,409 B1 (Nielsen et al); 6,157,449 (Hajduk et al); 6,151,123 (Nielsen); 6,034,775 (McFarland et al); 5,959,297 (Weinberg et al), all of which are hereby expressly incorporated by reference herein.
A high throughput viscometer is taught in U.S. application Ser. No. 09/578,997, filed May 25, 2000 (xe2x80x9cHigh Throughput Viscometer and Method of Using the Samexe2x80x9d) hereby expressly incorporated by reference herein.
In accordance with one preferred embodiment of the present invention, a library of materials is screened for rheological properties, such as viscosity. A force is applied to a library of materials while the materials reside within their respective regions of a common substrate. The relative flow resistance of the materials is measured in response to the force; and the materials in the library are analyzed and ranked based on the monitored flow resistance.
In another preferred embodiment, a plurality of liquid samples is screened for viscosity, where a library is provided having at least four different samples, and the viscosity of each of the samples is measured serially at a throughput rate no greater than about 10 minutes per sample.
In another preferred embodiment, a plurality of liquid samples is screened for viscosity, where a library is provided having at least four different samples, and the viscosity of at least two of the samples is measured simultaneously at a throughput rate no greater than about 10 minutes per library.